Furnace utilizing forced draft



May 21, 1929. E. A, MCARTHU'R 1,714,432

FURNACE UTILIZING FORCED DRAFT Filed Feb. 16, 1927 4 Sheets-Sheet l -INVENTOR Zmem/Z Mfg 76101" ATTORNEY May 21, 1929.

E. A. M ARTHUR FURNACE UTILIZING FORCED DRAFT Filed Feb. l6, 1927 4 Sheets-Sheet 2 v INVENTOR cflr'fikur 3450M 16,

liner/7,

ATTORNEY May 21, 1929. E. A. MCARTHUR l 7l4,432

FURNACE UTILIZING FORCED DRAFT Filed Feb. 16, 1927 4 Sheets-Sheet 5 ATTORNEY E. A. MCARTHUR 1. 14.432

FURNACE UTILIZING FORCED DRAFT Filed Feb. l6, 192'? 4 Sheets-Sheet 4 May 21, 1929.

*6 ATTORNEY Patented May 21, 1929.

UNITED STATES ELMER AIMOS MCARTHUR, OF FLINT, MICHIGAN.

FURNACE UTILIZING FORGED DRAFT.

Application filed February 16, 1927.

This invention relates to an improvementin furnaces utilizing forced draft.

The object of the invention is to provide a furnace of this character which when associated with a boiler will maintain a substantially constant pressure of steam in the boiler, the steam pressure being utilized to control the operation of novel instrumentalitics which regulate the amount of air flowing into the furnace, the amount of air flowing into the furnace being adapted to control a novel set of dampers associated. with the grate to regulate the passage of air through the grate and this same set of dampers controls the operation of an automatic stoker associated with the furnace. In general the steam pressure controls the forced. draft passing through the grate and the forced draft controls the amount of fuel supplied to the grate or combustion chamber.

Other objects and advantages reside in certain novel features of the construction, arrangement and combination of parts which will be hereinafter more fully described and particularly pointed out in the appended claims, reference being had to the accompanying drawings forming a part of this specification, and in which Figure 1 is a view partly in side elevation and partly in longitudinal vertical section showing a furnace and boiler assembly having the present invention organized therewith,

Figure 2 is a fragmentary view lllllll' to i 1 but illustrating only the bat arraiugc nient, grate, stoker and stolrer control,

l igure 3 a f1'ag inentary detail view i lustrating the operation of the strohe-clianging mechanism of the stoker control,

Figure 4; is a perspective view show, t, automatic 1 atlle or damper arrangement together with the stoher and )liOi' control means,

if i 'ure 5 is a view partly in elevation and partly in. section showing the mechanism employed to permit the steam pressure to control the amount of ai supplied to the grate or chamber below the grate, and

Figure 6 is a fragmentary vertical section showing the resilient connection between a lever and an operating shaft.

l'lefcrring to the drawings the numeral 1 designates generally a fur ace which has a grate 2 made up of closely spaced bars 3 and rather widely spaced bars 4. It is to be understood, however, that the construction of Serial No. 168,745.

the grate may be varied without departing from the present invention. Below the grate 2 a chamber 5 is provided, this chamber being substantially closed, the only outlet of the chamber being through the combustion chamber 6 by Way of the grate 2. Water tubes 7 of the boiler 8 extend through the upper portion of the combustion chamber.

Fuel is supplied to the grate from a hopper 1 0 which has a chute 11 extending down t o a fuel supply opening 12, the opening 12 being located opposite a lateral branch 12') of the chute 11 in which branch a ram 14 of stolrer, designated generally 15, The stoker 15 may be of any suitable or conventional type and in the present application a Jones type of stolcer is shown. A illustrated to advantage in Fig. 2 the ram 13 is carried t the forward end of a L iston rod 16 connected to a piston 17, the piston 1'7 operating in a cylinder 18. Steam or other motive liui r supplied to the cylinder under the control of valve mechanism, not shown, and this steam or motive fluid 01c ates to reciprocate the piston 1'7 and consequently the ram 13. The movement of the ram 18 back and forth results in the feeding of the coal or the fuel from the chute 11 onto the grate.

In the pit 20 below the boiler room a boxing 21 is provided and to this boxing 21 air under a substantially constant pressure is sup plied. Any suitable means may be provided for supplying the air under constant pressure to this boxing 21 and for the sake of illustration such a means is shown as a motor operated fan A conduit 23 leads from the boxing 21. into the chamber 5 and the pasof the air throu h the conduit 28 into the chamber 5 is controlled by means of a damper mounted on a shaft rotatably supported in bearings provided therefor in the conduit 23.

lVithin the chamber 5 an ai'itomatic baffle arrangement provided for controlling the ar unit of air and the eistribution of air which passes through. the grate. This battle arrangenient comprises a shaft 230 rotatably mounted in sn' able bearings provided therefor. Adjacent the ends of the shaft discs 31 are lined thereto. These discs have arcuato slots 32 therein with which. bolts and nuts 33 co -act, the bolts and nuts on serving to adjr tallv secure to the discs 31 a main ballie The battle 34; includes side bars 35 rotatably mounted onthe shaft 30 and carrying a fixed body plate 36 and a swinging wing or plate 37, the plate 37 being hinged, as at 38, to the plate so. lt is the bars that are adjustably fastened to the discs 31 by the bolts and nuts 33 and this permits the main battle or damper to close at the desired time inasmuch as it may be adjusted angularly relative to the shaft 30 and the discs 31. iL swinging vane 40 is provided and is pivotally connected, as at 451., to the lower ends of the arms 42, the arms 12 being loosely mounted at their upper ends on the shaft ill). 'l hesc arms -.l-2 are connected to the bars 3;) by means of longitudinally adjustable links 4-3, the sections of the links 4:3 being fastened or otherwise suitably connect ed to the bars and arms l-L and being adjustably clamped to each other by means of bolts and nuts -l-lextending through aligned slots !:5 in the sections of the link. Similar, though longer, links l6 are provided for corn nccting the ane 40 with the pivoted section 37 of the main batlle, the links being longitudinally adjustable though rigid in any adjustment and having their ends pivotally connected to the section 37 and vane 41:0. ililcans is pro *ided tending to maintain the pivoted section 37 in an open position, that is, in the position shown in Fig. 1, and. this means prefe ably comprises a pair of. rods having turnbiiickles 51 incorporated therein to make the rods of adjustable length. The rods 51 have their upper ends connected, as at; so, to the section 37 and have their lower ends connected to springs 58, the springs 58 being in turn connected by means of links 59 to the arms With the arrangen'ient thus far described the blast that blows in through the conduit 23 encounters the main ballle 3i and when this blast is at its height it will swing this main batlle Ell upwardly from the dotted line position of Fig. 2 to the full line position of Fig. 1. This results in the interposition of the battle 34: between the grate and the blast as to reduce to some extent the amount of air passing through the grate. Then it the strength of the blast is maintained it will act on the *ane 40 to swing the same from the full line position shown in Fig. l to the full line position shown in Fig. 2, thereby completely closing ell that sect-ion of the grate made up of the closely spaced bars 3 and causing all the blast: of air to pass through the lo ver portion of the grate made up of the grate bars 4:.

The position of the balllc arrangement in the chan'iber regulates or controls the opera tion of the stoker and this control or regulation is elliected by utilizing the motion of the discs 31 to autonnitiatlly change or any the stroke f the ram 13 of the stokcr. In carrying out this purpose the discs 31 are provided with can'nning ribs (50 eooperable with rollers (51 provided at the ends of the le .'e"s (32, the levers (19. being fixed to a shaft-(l3 having a slotted arm til secured thereto and connected with the lower end of a connecting rod by means of a pin (30 ope -ating in the slot of the arn'i G l. buckle 67 is interpositioned between the sections of the rod (35 to provide Variation in lergth of the link. The upper end of this rod 65 is connected to a bell crank lever fulcrumed, as at 69, adjacent the outer end of a hand lever 70. The hand lever 70 is fixed 'to a shaft '21 rotatably mounted in suitable l rackets and disposed adjacent to a quadrant '4' 'lfhis quadrant has a single notch T3 with. which a spring-pressed detent T l is adapted to enga 'lhe detent T l: is controlled from the bell crank lever 68 through the medium of a wire or wiredike rod 75. The shaft 71 has an arm It; loosely mounted thereon and resiliently connected therei ith. by means of a spring "Z7 lutving one end anchored, as at 78, in the shaft 'i'l and having its opposite end engaged with the arm 76. The outer end of this arm 76 *arries a roller 79 and the roller 79 is engaged with the uiiderside of a pivoted plate 80 having a yoke 81 at one end pivotally mounted, as at 82, on a stationary b 'acket 83. 'l. he bracket is formed with a longitudinal slot 84- extending entirely through the same. ln this slot a depending bar 85, which is rigidly connected with the ram 13 of the stoker, ope ates. The bar 85 may be guided in a back and forth movement in the slot of the b 'acl-zet by means of a lateral pin 86 operating in a guide slot 87. A wedge 88 is positionet. for sliding movement up and down in the slot 8% of the bracket 83, the wedge being constrained to sliding movement and held against displacement from the slot 8-1 by means of the pin 85) ope 'ating in a slot 90 of the wedge. The bottom or large end of the wedge preferably has a roller 92 mounted thereon and engageable with the pivoted plate 80.

ll ith this construction who '1 the l allle arrangement entirely open, sh wn in not ted lines in Fig. 2, the wedge member 88 in lowest:- position in the slot tll; ram 1': of the stokcr is rcciprocated on its longest stroke and is charging the with fuel at its greatest cajnicity. l halite. arra einent clos s, the cams on the discs 31 swing the lever arms (32 to release the detent and force the hand lever '70 in z. clockwise direction as viewed in Figs. 1. n and 3, whereby the wedge member all elevated and the stroke of the steker is ened so that less is :uAOl'tfuel is delivered onto the grate of the furnace.

The boiler pressure is utilized to control the damper 2i and consequently t e-control the amount of the blast blown through the conduit 23 into the chamber 5 and in carrying out this purpose the pipe line leads from the steam space of the boiler and connects with a sliding valve casing 101. The sliding valve casing 101 has a partition 102 therein and in the partition ports i023 and The hand wheel operated turn-- ii: Li

are provided. The valve ca J c tiet coupled to pipe 165 havr 1 a branch ieading into the lower end of a Cy 07 and a brai ch 108 ieading into tlnd of this cylinder. A rotary valve, d m nated generally at 109, is incorporated in the b 'anch 106 and comprises a "as :g 110 haw a partition 111 formed with an inlet port 112 and an inlet port 113. A single outlet portion 111 is provided and leads to the cylinder 107. An ianst or vent to the fliinlbrr phere is also provided and designated at 11:" his exhaust or vent to the atmospi controiied by a rotary plug valve 116. 1 i e casing 110 a main va "7 red and has a diametrical port 1 radial, port 119. the port 1.18 being "ed successively register with the 12 and 118 and the port 119 being do ter with too vent 1.15 in cert pcration. The port 118 is in ration vith the outlet port 11 1; at a;

The brancn 108 has a valve ca 'icorporated therein, the valve casin Y avinp' partition 121 nm ed with a g'le inlet port 122. This casing 1. .1, also an outlet port 123 and a vent ed by a rotary valvering a main v clve body 126 is re fitted, the main 1 ve body 126 haviir metrical port 127 always in re tration ext,

ti 0 mt and :dt d to be regisi'e ed w or et port 1 a or to be blocked by the partition 121. A radial port 128 .15 also mmi wi ew) 1 icimee in u1e mam valve bony 126 and leans i'rom the port 127 out th ough the periphery o. the o body, this port 128 having been ed to nster vrth the vent- 12 1 in ccr- -.s a hand-controlled vaive 180 as to accelerate or re the escape of the steam thcroti' vaive 130 has an arm 132 fixed 1' 1 connected with a link 1213, the 1 1 1." also being connected to a lever 181-.

end ot the link 1788 is connecte 13-1 iuicrumcd on a clamp 13: 1 br nch 108 of the 81111111 line.

31. Jenn-eetedv by a rod. 136 or other n t ansmission means to a suitable conlever at any desirabie point. The entry valve body 17 of the valve 102 has r 1410 first thereto, this arm 140 being connected to the iO'WGI' end of a lever umed, as at 112, on a link 1413 carried cyiinder 107. This san e lever 1 11 is ed by means of a link 115 with an arm d. to the valve The lever 111 has 1 slot connection 117 with a shittal 1e "he sh 'itabie rod 118 being connected 1mg valve 14-9 traveling over the var 102 and raving ports and 151 c ith the ports of the perti'ioii. osite end of the shiitable roo 1 -8 is l on the upper end of a 1 I roe .161 extending upwzrdly from piston 162 operating in the cylinder 107. 1 second gea r s gment meshes with the segment the gear segment 163 being pivotally mounted, as at 161, on the frame 157. he gear segment also has an arm 165 integrai therewith, the arm 165 bei con nected by means of a connecting rod 166 with an arm 168 fined to a giar 169 pivotally mounted on the conduit 23 and meshing with he gear wheei 25 which is fixed to the axle of the damper.

The rod 118 is releasably held in several of its adjusted positions by means of a la ch 170 co-operable with notches 172 in the rod 118. The latch 170 fixed to a slidin block 174 mounted in bracket 175 earried on the frame 157, the block 171 having a stem 176 slidably titted through a guide bar 178 of the bracket 17? and carrying a nut 1'79 to limit the downwai i. movement of the sliding block 171. A spring 180 encircles the stem 17 6 and is compressed and arranged to force the block 17 downwardly. The lower end of the block carries a roller 181 engaging with a cam 182 formed on the gear segment 155. The pin 153 which operates in the cam slot 151 has a rod 185 pivotally connected thereto, the rod 185 extending loosely through an opening 186 provided in an arm 186 formed on the gear segment 163. The upper end of this rod 185 is threaded and has a nut 187 adjustably mounted thereon, the nut engaging the upper end of the coil spring 188 and encircling the rod and having its lower end abutting a rounded washer 188 looseiy mounted on the rod 185 and engaging the arm 1863,

Referring more particularly to Fig. 5, it will be seen that the v rious elements which are operated through seam pressure are in rich a position that steam from pipe 100 3assing i'zhrough ports 151 and 103 enters pipes 105 and 106 and is acting on the under face of the piston 162 tl ereby maintaining the piston in its up 'ierinostposition. \Vhen the damper 21 is first turned to horizontal position and air is permitted to enter the chamber 5 of the furnace which is be1ow the grate, the bar-lie 3 1 is in the dotted line position shown in F 2. In such position the cam member 88 is in its lowermost position, shown in Fig. 3, whereby the ram 18 of the stoker is permitted its full working stroke. The pipe 108 is exhausting through the port 127 and port 128 through the valve 125 and through the restricted vent 1% whereby the piston 162 is cushioned on its up stroke.

lVith the daniper 2'1 open, a full iorce draft is had which acts on the plate and plate 30 thereby elevating the frame 3% to its upper most position and closing the battle 37, as in dicated in full lines in Fig. 2. The arm 76 is moved to its most elevated position, raising the member 80 and thereby torcing the cam 88 into the position shown in F" thus limiting the stroke of the ram 13. the major portion of the air is cut ed to the grate 2, and the ram 13 is limited in its stolzing operation, the lire bed will naturally be decreased in density so that the pressure ot the steam is not sutlicient to maintain the piston 102 in its most elc ated position against the weight 150, said pston will fall thereby closing the port 118 with the valve 117 and cutting oil communication between the sections ot the pipe 106 at opposite sides of the valve 117. The port 119 will then register with the discharge port 115 and steam from cylinder 10'1- below piston 162 will be exhausted. At this time the port 107 will register with the port- 122 thereby admitting steam through pipe 108 tl'irough cylinder 10"? above piston 162. As the piston 102 is lowered, arm 158 will fall causing the cam memher to engage the roller 181 raising the meniher 17% and likewise the latch 170 from the notch 172, and as the rod 148 is moved in the direction indicated by the arrow in Fig. 5, the latch 170 will drop into notch 173 and maintain rod 148 against further movement. As the lever or arm 158 moves downwardly the segi'nental gear 155 being in mesh with the segmental gear 103 will actuate the gear 163 moving the arm 165 and likewise arm 10S downwardly rocking the gear 169. This causes rotation of gear 25 and actuation of the damper 24 to the dotted line position shown in Fig. Since the air draft is cut oil" :trom the pipe -f3 the battle Set will no longer be sustained in its elevated position and will tell. to the dotted line position shown in Fig. 53, thereby permitting air to pass through the chamber 5 around the plate 3'? and through the opening in the frame or battle ill and through the grate 2. At this time the lever 70 is moved downwardly thereby permitting the cam 88 to be moved from the bracket 83 so that the rain 13 ot the stoker will be permitted its full power stroke, thereby placing the greater quantity of coal on the grate while at the same time air passes up through the grate for stimulating the fire which will thus increase the pressure of the steam in the boiler.

I claim 1. The combination with a boiler having a grate, stolting means "for supplying t'uel to the grate, a chamber below the grate, n'ieans for supplying air under pressure to the chamber, of a battle ar alignment in the chamber having surfaces exposed to the blast of air whereby the battle arrangement is automatirally controlled to regulate the amount of air pas mg to the grate in accordance with the draft passing through the chamber, means regulated in its action by the position of the battle arrangement for controlling said stoking means, a damper for controlling the supply of air to the chamber, and means con trolled by the boiler pressure for opening and closing said damper.

2. The combination with a furnace having a grate, a chamber below the grate, means for si'sppl vin air under pressure to the chamber, a batlle arrangementin said chamber for regulating the passage ot the air to the grate and comprls iing a main balile, means for mounting the main ballle :tor swinging movement, said main haillc having a pivoted. section, a vane suspended within the chamber for pivotal movement and disposed across the path of the air to the grate, and means for connecting the ane with the pivoted section of he main battle.

3. The combination with a boiler having a grate, a chamber below the grate, means :tior supplying air under pressure to said chamber, a damper for controlling the flow of air to the chamber, means responsive to the boiler pressure op ning and closing the damper and comprising a cylinder, a piston in the cylinder, a pair ot gear segments, one ot the gear segments having an arm operz tively connected to the damper, the other gear segment having an arm operatively connectcd to the piston, a steam line leading to the lower end of the cylinder, a sliding valve incorporated in the steam line, a shifting rod connected to the sliding valve and to one of said gear segments, a rotary valve also incorporated in the steam line and having a valve controlled vent to the atmosphere, and motion transnnission devices between the rotary valve and the valve of the vent and the shifting rod for automatically operating the same.

a. The combination with a boiler having a grate, a chamber below the grate, means for supplying air under pressure to said chamber, a dan'iper for controlling the flow oat air to the chamber, means responsive to the boiler pressure open and closingthe damper and comprising a. cylinder, a piston in the cylinder, a pair of gear segments, one of the gear segments having an arm operatively connected to the damper, the other gear segment having an arm operatively connect ed to the piston, a steam line leading to the lower end of the cylinder, a sliding valve incorporated in the steam line, a shifting rod connected to the sliding valve and to one of said gear segments, a rotary valve also incorporated in the steam line and having a valve controlled vent to the atmosphere, motion transmission devices between the rotary valve and the valve of the vent and the shitting rod for automatically operating the same,

said steam line having a branch leading into the upper end of the cylinder to provide a cushion, a rotary valve incorporated in said branch, and motion transmission means between the shifting rod and said rotary valve.

5. The combination with a furnace having a grate, a boiler heated by the furnace, a chamber below the grate, means for supplying air under pressure to the chamber, a battle swingably mounted in the chamber in the ath of the air in an open position and adapted to engage the grate when in a closed position for cutting of]? the air to the grate, a damper for controlling the flow of air through the chamber, means responsive to the pressure of the boiler for causing openingand closing of the damper thereby controlling the position of the baiiie, said bafile being provided ith an opening, a valve for closing said opening, a vane swin ably connccted to the battle and 2L(l tt6(l to be actuated by the air and means connecting the valve with the vane so that when the vane is moved in one direction the valve will be closed.

ELMER AMOS MGARTHUR. 

